package com.styleman.wetalk.db;

 

import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;

public class DBHelper extends SQLiteOpenHelper {

	private static final String DATABASE_NAME = "test.db";
	private static final int DATABASE_VERSION = 1;
	
	public DBHelper(Context context) {
		//CursorFactory设置为null,使用默认值
		super(context, DATABASE_NAME, null, DATABASE_VERSION);
	}

	//数据库第一次被创建时onCreate会被调用
	@Override
	public void onCreate(SQLiteDatabase db) {
		db.execSQL("CREATE TABLE IF NOT EXISTS tb_friendmsg" +
				"(id INTEGER PRIMARY KEY  , createTime TEXT, send INTEGER , _to INTEGER, content TEXT)");
	}

	//如果DATABASE_VERSION值被改为2,系统发现现有数据库版本不同,即会调用onUpgrade
	@Override
	public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
		db.execSQL("ALTER TABLE person ADD COLUMN other STRING");
	}
 
}
